The invention relates to an electrodeless low-pressure discharge lamp comprising a glass lamp vessel which is sealed in a gas-tight manner and is filled with a metal vapor and a rare gas. The lamp is provided with a core of magnetic material, while during operation of the lamp, an electric discharge is maintained in the lamp vessel by means of a wire winding connected to a high-frequency supply unit and arranged to surround the core. Such a lamp is known from Netherlands Patent Application No. 8301032 laid open to public inspection, and corresponding U.S. Pat. No. 4,622,495 issued Nov. 11, 1986.
The lamp described in this patent application has such dimensions that it can be readily screwed into a fitting for incandescent lamps. The supply unit in the lamp comprises a high-frequency oscillator circuit having a frequency higher than about 20 kHz. However, it has been found that during operation of the lamp high-frequency interference currents originating from the lamp are liable to be produced in the conductors of the supply mains. There is a risk that the lamp then no longer satisifes international standards imposed with respect to conducted interference currents.
The invention has for its object to provide an electrodeless low-pressure discharge lamp, in which the strength of the interference currents generated by the lamp in the conductors of the supply mains is reduced to a comparatively low level.